Christopher M Constantine

US Patent:

6544696, Apr 8, 2003

Filed:

Nov 30, 2001

Appl. No.:

09/996748

Inventors:

Russell Westerman - Largo FL
Christopher Constantine - Safety Harbor FL

Assignee:

Unaxis USA Inc. - St. Petersburg FL

International Classification:

G03F 900

US Classification:

430 5

Abstract:

An embedded attenuated phase shift mask (âEAPSMâ) includes an etch stop layer that can be plasma etched in a process that is highly selective to the underlying quartz substrate. Selectivity to the underlying quartz maintains a desired 180 degree phase shift uniformly across the active mask area. Conventional plasma etching techniques can be utilized without damage to the underlying quartz substrate. Alternatively, the etch stop layer comprises a transparent material that can remain intact in the mask structure.